/// <summary>
/// Calculates ratings
/// </summary>
public void CalculateRatings()
{
_ratings = new Dictionary<int, MaxCoefficient>();
var rowsCount = _rows.Count;
foreach (var variableId in _allVariables.Keys)
{
var rating = new MaxCoefficient();
for (var rowIndex = 0; rowIndex < rowsCount; rowIndex++)
{
var tmp = new MaxCoefficient(_targetFunctionCoefficients[_basisVariables[rowIndex]]);
var fraction = new Fraction(_rows[rowIndex].ElementAt(variableId));
tmp.Multiply(fraction);
rating.Add(tmp);
}
rating.Subtract(_targetFunctionCoefficients[variableId]);
_ratings.Add(variableId, rating);
}
FunctionValue = CalculateFunctionValue();
}
/// <summary>
/// Returns index of solving cell(or -1 if table has no positive rating)
/// </summary>
/// <param name="table">Table with calculated ratings</param>
/// <param name="solvingRowIndex">Index of solving row</param>
private int GetSolvingCellIndex(SimplexTable table, int solvingRowIndex)
{
if (solvingRowIndex < 0) return -1;
var minRatioIndex = -1;
var minRatio = new MaxCoefficient();
for (var i = 0; i < table.Variables.Count; i++)
{
var matrixElement = table.GetMatrixElement(solvingRowIndex, i);
if (matrixElement >= 0) continue;
var rating = table.Ratings[i];
var currRatio = new MaxCoefficient(rating);
currRatio.Multiply(1 / matrixElement);
if (currRatio.CompareTo(minRatio) != -1 && minRatioIndex != -1) continue;
minRatioIndex = i;
minRatio = currRatio;
}
return minRatioIndex;
}
/// <summary>
/// Gets function value
/// </summary>
public MaxCoefficient CalculateFunctionValue()
{
var tmpResult = new MaxCoefficient();
foreach (var elem in _basisVariables)
{
var varCoefficient = new MaxCoefficient(_targetFunctionCoefficients[elem.Value]);
var varValue = new Fraction(_freeCoefficients[elem.Key]);
varCoefficient.Multiply(varValue);
tmpResult.Add(varCoefficient);
}
return tmpResult;
}